Re: DC TC
> I found an artical where someone built a large auto transformer that
> produced 42" sparks from a battery power supply. It's not TC either.
Be interested in seeing more about this.
> Many years ago I built a crude Tesla Coil using a DC power supply an 810
> tube and a signal generator to drive the control grid.
> It seem to me if a DC power source could be pulsed at resonate frequency
> it would work fine for a Tesla Coil.
> The next question is what is the best way to pulse a DC power supply
> with out a tube? How about a DC power supply with an adjustable charge
> rate for the capacitor bank. The discharge rate threw the spark gap
> could be adjusted to find resonate frequency? The capacitors would have
> to be sized correctly for the proper charge rate.
That implies a real low TC frequency and a real high break rate (CW
operation). Not a simple proposition. CW operation implies pretty much
continuous secondary loading which means the coil will never attain
the high voltages you can get in a more slowly pulsed coil. A coil
operated with, say, one cap discharge per 10 secondary oscillations
imposes some pretty daunting requirements on both the charging circuit
and gap system. I tried exactly this using a precision (uS type
precision) pulse generator triggering a MOSFET "gap" on a low powered
coil during some expts last year. Far from easy even with that gear
and it was stunningly sensitive to objects in the vicinity. I got the
break rate up to that of the coil but the capacitor voltage was
sagging badly as a result, even with a small boost choke. In fact,
the power supply almost needs to be resonant at Fs as well to do it
properly. Technically this is approaching Class-C operation.
> With a Tesla Coils operating on a DC power supply it seem like the
> toroid or sphere on top of the secondary would charge up in one polarity
> like a Van De Graff generator.
It is a power oscillator. It cannot be pumped up DC-wise because the
secondary is a piece of wire connecting the toroid to ground. It has,
as you say, a resonant frequency. You could elevate the entire coil
DC-wise by inserting a DC supply between ground and the bottom of the
secondary (a la Greg).